1. Field of the Invention
The present invention relates to a data transmission system and method, and more particularly, to a data transmission system and method which monitors a decoding condition of a slave device to correspondingly switch a transmission mode between a master device and a slave device.
2. Description of the Prior Art
As technology advances, mobile devices, such as smart phones and the personal digital assistants (PDA), have integrated more communication and display functions to implement various application functions. In order to deal with such various application functions, a high speed processing interface between a processer and a display panel of the mobile device is necessary to increase data transmission amounts, so as to improve the touch and resolution functions of the display panel. Under such circumstances, the leading industrial producers have provided the mobile industry processor interface (MIPI) to standardize communication among the mobile devices.
Please refer to FIG. 1, which illustrates a schematic diagram of a conventional data transmission system 10. As shown in FIG. 1, the data transmission system 10 comprises a master device 100, such as a master system microprocessor, and a slave device 120, such as a display device microprocessor. The master device 100 encodes an original packet P_Ori to be a transmission packet P_Tra and transmits the transmission packet P_Tra to the slave device 120, wherein the transmission packet P_Tra comprises an original clock packet and an original data packet. The slave device 120 receives the transmission packet P_Tra, and accordingly, decodes the transmission packet P_Tra to be the original packet P_Ori, so as to transmit the original packet P_Ori to a display device 140 for displaying. Noticeably, the MIPI comprises two kinds of transmission modes. One of the transmission modes is the low power transmission mode, and the other is the high speed transmission mode. When the master device 100 transmits a plurality of display information (i.e. the plurality of original packets) to be displayed on the display device 140 to the slave device 120, the master device 100 is operated in the high speed transmission mode. Under such circumstances, the plurality of display information is encoded to be the plurality of transmission packets P_Tra, and a differential signal transmission process is utilized for transmitting the plurality of transmission packets P_Tra to the slave device 120. When the master device 100 does not transmit the plurality of display information, the master device 100 is operated in the low power transmission mode to wait for another command of entering into the high speed transmission mode. Noticeably, the differential signal transmission process of the high speed transmission mode can increase the transmission rate between the master device 100 and the slave device 120, to effectively reduce a pin number of the master device 100 and the slave device 120, so as to comply with the operation of larger data transmission amounts.
Please refer to FIG. 2A to FIG. 2C, where FIG. 2A to FIG. 2C illustrate schematic diagrams of processing different data transmission signals between the master device 100 and the slave device 120. The transmission packet P_Tra comprises frame data D_Frame1-D_FrameN, and each of the frame data D_Frame1-D_FrameN comprises row data D_Line1-D_LineM, wherein the symbols N, M represent the resolution of the display device 140 and can be adaptively adjusted. The low power transmission mode corresponds to a high voltage pulse signal, such as 1.2 volts, and the high speed transmission mode corresponds to a low voltage pulse signal, such as 300 micro-volts. As shown in FIG. 2A to FIG. 2C, when the master device 100 and the slave device 120 are ready for transmitting the display device information, which means that the low power transmission mode is switched to the high speed transmission mode, the data transmission signals are correspondingly changed from the high voltage pulse signal to the low voltage pulse signal, so as to transmit the display device information. Accordingly, the frame data D_Frame1-D_FrameN of the transmission packet P_Tra as well as the line data D_Line1-D_LineM of each of the frame data D_Frame1-D_FrameN are transmitted via the high speed transmission mode, and the data transmission signals are represented as the low voltage pulse signal. However, FIG. 2A to FIG. 2C demonstrate different transmission processes for transmitting the display device information between the low power transmission mode and the high speed transmission mode, respectively. As shown in FIG. 2A, the signal between every two row data corresponding to the high speed transmission mode goes back to the low power transmission mode once. As shown in FIG. 2B, the signal between every two frame data corresponding to the high speed transmission mode goes back to the low power transmission mode once. As shown in FIG. 2C, once the master device 100 is operated in the high speed transmission mode, the master device 100 is switched to the low power transmission mode after transmitting all the frame data D_Frame1-D_FrameN of the transmission packet P_Tra as well as the line data D_Line1-D_LineM of each of the frame data D_Frame1-D_FrameN.
Noticeably, during processing in the low power transmission mode or in the high speed transmission mode, the master device 100 cannot monitor whether the slave device 120 correctively receives and decodes the transmission packet P_Tra. If errors occur while transmission (i.e. the transmission packet P_Tra has errors) and the master device 100 is operated in the high speed transmission mode, the user has no chances to correct the errors of the transmission packet P_Tra. Thus, the master device 100 will be switched to the low power transmission mode first, and then be operated in the high speed transmission mode again for related transmission, such that the slave device 120 can correspondingly receive the correct transmission packet P_Tra. Under such circumstances, the master device 100 may not instantaneously notice that the slave device 120 has missed partial transmission packets P_Tra, and the high speed transmission mode is still operated for transmitting the display device information. Further, if the user requires more accuracy as well as stability of transmission and operates the master device 100 to be switched between the high speed transmission mode and the low power transmission mode, a transmission amount of the transmission packet is correspondingly restricted to narrow the application range of the data transmission system 10.
Therefore, it is an important issue to provide another data transmission system and method which can adaptively switch a transmission mode between a master device and a slave device, such that an original data can be correctly received and decoded by the slave device, and in the meanwhile, the unnecessary waiting periods as well as the operational powers can be correspondingly saved during the transmission process.